In certain applications, components of electrical systems are water cooled. In such electrical systems, a plenum is formed from sheet metal or another thermally conductive material. An exterior surface of the sheet metal or other thermally conductive material is arranged in contact (or conductive communication) with heat-generating components of the electrical system. Water, often treated with chemicals to avoid corrosion, flows through the plenum. Heat from the components of the electrical system is transferred to the sheet metal or other thermally conductive material and then to the water in the plenum. The water flowing through the plenum transports the heat away from the components of electrical system, thereby keeping the components cool.